1. Field of the Invention
The technical scope of the invention is that of priming devices (fuses) for spin-stabilized projectiles and in particular that of safety and arming devices equipping such priming devices.
2. Description of the Related Art
Spin-stabilized explosive projectiles, and in particular medium caliber projectiles (caliber of less than 50 mm), more often than not incorporate a safety and arming device that incorporates a rotor for the primer that is released further to the projectile being fired. This rotor has an out-of-balance that ensures the alignment of the primer with the rest of the pyrotechnic priming train.
Patents FR-2689972 and FR-2533686 describe such safety and arming devices. The out-of-balance rotor is put into place in a cage that is free to rotate with respect to the projectile's axis.
One drawback to these known devices lies in that they require a primer (thus a pyrotechnic component) to be put in place on the rotor. The primer must, in addition, be of a relatively small size for medium caliber applications (caliber of less than 50 mm).
Another drawback is that, if this solution is well adapted to projectiles in which the rotor primer is initiated by percussion, it is more difficult to implement for a projectile in which the primer is initiated by an electric current supplied by electronic fire control means. Such functioning modes are employed when projectiles are to be made that use a programmable timer fuse.
It is, in fact, difficult to make flexible conductors that are able to accompany the pivoting of the primer rotor without disturbing the latter's movement.
A safety and arming device is known by patent EP-1780495 that comprises a screen formed by two half-screens that obstruct a transmission channel linking a detonator and a pyrotechnic relay.
These half-screens are mobile via the action of motor means, for example one or several springs, released by electronically-controlled locks.
Such a solution is particularly well adapted to production in the form of micro electro-mechanical integrated circuits. However, to produce screens of larger sizes, the motor means or control locks become difficult to integrate, in particular in a medium-caliber projectile.